using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing.Design;
using System.Text;
using System.Windows.Forms;
using System.Windows.Forms.Design;

namespace DevComponents.Charts.Design
{
    #region FlagsEnumUIEditor

    public class FlagsEnumUIEditor : UITypeEditor
    {
        private FlagsCheckedListBox _FlagCb;

        public FlagsEnumUIEditor()
        {
            _FlagCb = new FlagsCheckedListBox();
        }

        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return (UITypeEditorEditStyle.DropDown);
        }

        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            if (context != null && context.Instance != null && provider != null)
            {
                IWindowsFormsEditorService edSvc =
                    (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));

                if (edSvc != null)
                {
                    Enum e = (Enum)Convert.ChangeType(value, context.PropertyDescriptor.PropertyType);

                    _FlagCb.Value = e;
                    edSvc.DropDownControl(_FlagCb);

                    return (_FlagCb.Value);
                }
            }

            return (base.EditValue(provider, value));
        }
    }

    #endregion

    public class FlagsCheckedListBox : CheckedListBox
    {
        private Type _Type;
        private Enum _Value;
        private bool _UpdatingStates;

        public FlagsCheckedListBox()
        {
            CheckOnClick = true;
            BorderStyle = BorderStyle.None;
        }

        #region Public properties

        #region Value

        public Enum Value
        {
            get
            {
                return (_Value);
            }

            set
            {
                _Value = value;
                _Type = value.GetType();

                InitializeCheckedListBox();
            }
        }

        #endregion

        #endregion

        #region InitializeCheckedListBox

        private void InitializeCheckedListBox()
        {
            Items.Clear();

            foreach (string name in Enum.GetNames(_Type))
            {
                object o = Enum.Parse(_Type, name);
                uint value = (uint)Convert.ChangeType(o, typeof(uint));

                FlagsCheckedListBoxItem item = new FlagsCheckedListBoxItem(value, name);

                Items.Add(item);
            }

            SetCheckedItems();
        }

        #region OnItemCheck

        protected override void OnItemCheck(ItemCheckEventArgs e)
        {
            base.OnItemCheck(e);

            if (_UpdatingStates == false)
            {
                FlagsCheckedListBoxItem item = Items[e.Index] as FlagsCheckedListBoxItem;

                uint sum;

                if (e.NewValue == CheckState.Checked &&
                    (item.Value == 0 || item.Text.Equals("None")))
                {
                    sum = item.Value;
                }
                else
                {
                    sum = CalculateCheckedSum();

                    if (e.NewValue == CheckState.Checked)
                        sum += item.Value;
                    else
                        sum -= item.Value;
                }
                   
                _Value = (Enum)(Enum.ToObject(_Type, sum));

                SetCheckedItems();
            }
        }

        #endregion

        #region SetCheckedItems

        private void SetCheckedItems()
        {
            _UpdatingStates = true;

            int value = (int)Convert.ChangeType(_Value, typeof(int));

            for (int i = 0; i < Items.Count; i++)
            {
                FlagsCheckedListBoxItem item = Items[i] as FlagsCheckedListBoxItem;

                if (item.Value == 0)
                    SetItemChecked(i, value == 0);

                else if (item.Text.Equals("None"))
                    SetItemChecked(i, value == item.Value);

                else
                    SetItemChecked(i, ((item.Value & value) == item.Value));
            }

            _UpdatingStates = false;
        }

        #endregion

        #endregion

        #region CalculateCheckedSum

        private uint CalculateCheckedSum()
        {
            uint sum = 0;

            for (int i = 0; i < Items.Count; i++)
            {
                FlagsCheckedListBoxItem item = Items[i] as FlagsCheckedListBoxItem;

                if (GetItemChecked(i))
                    sum |= item.Value;
            }

            return (sum);
        }

        #endregion
    }

    #region FlagsCheckedListBoxItem

    public class FlagsCheckedListBoxItem
    {
        public uint Value;
        public string Text;

        public FlagsCheckedListBoxItem(uint value, string text)
        {
            Value = value;
            Text = text;
        }

        public override string ToString()
        {
            return (Text);
        }
    }

    #endregion
}